The patella is a complex sesamoid bone within the quadriceps enhancing mechanical advantage of the extensor mechanism. Depending on activity, the patella magnifies either force or displacement; behaving as a lever, by redirecting quadriceps force it also acts as a pulley. Aim. We describe and validate a device for obtaining consistent dynamic weight bearing views of the patellofemoral joint (PFJ). Materials and Methods. Weight bearing (WB) axial views of 48 knees (24 patients) were performed using the device. The sulcus angle (SA), congruence angle (CA), lateral patellofemoral angle (LPFA), facet angle (FA) and patellofemoral displacement (PD) were measured. These were compared with similar measurements made on prone (PR) and axial (AX) radiographs of same knees. Results. Variance (V=SD2) and Standard error of mean (SEM/95% CI) for all measurements in each of the three views were analysed. For the Sulcus Angle, Congruence angle and LPFA, the WB view had the lowest SEM and the least variance in comparison to PR and AX views (SEM 1.05/V 30.14, SEM 2.52/V 172.39 and SEM 1.34/V 47.61 respectively for the SA, SEM 3.09/V 256, SEM 2.79/V 210.25 and SEM 3.37/V 306.25 respectively for the CA, SEM 0.67/V 11.9, SEM 1.20/V39.06 and SEM 1.03/V 28.83 respectively for the LPFA). SEM and Variance for FA measurements were similar for WB and AX views but superior to PR views (SEM 1.62/V 70.56, SEM 1.6/V 68.9 and SEM 2.3/V 148.84 respectively). Mean PFD was maximum on the WB view compared to the PR and AX views (36.0, −45.62 and 22.23 respectively) with lowest SEM and V (SEM 8.73/V 2052.0, SEM 18.65/V 92959.67 and SEM 9.70/V 2540.16 respectively). Conclusion. The WB view as introduced and reported here has consistently lower Variance, SEM and SD in comparison to Axial and Prone views for all measurements of the PFJ. WB view also gives a more accurate dynamic measure of Patello Femoral displacement. The view is easily obtained and readily reproduced

Introduction

Patellar tracking in total knee replacements has been extensively studied, but little is known about patellar tracking in isolated patellofemoral replacements. We compared patellar tracking and the position of the patellar groove in the natural knee, followed by implantation of the femoral component of a PFR (patella unresurfaced) and after implantation of the femoral & patellar component of the PFR.

The purpose of this study was to validate the usefulness of SPECT/CT as an evaluation method for determining treatment and prognosis for patellofemoral cartilage lesions, based on MRI and arthroscopic findings. From August 2009 to February 2010, SPECT/CT was performed on 80 patients (24 male and 56 female, average 53.3 years old) with chronic anterior knee pain who had no degenerative changes or patellar malalignment on plain radiographs. Radioisotope uptake findings on patellofemoral joint from SPECT/CT were classified into three grades by one nuclear medicine specialist. In the patients who demonstrated poor improvements after conservative treatments, MRI and arthroscopy were performed. Patellofemoral cartilage conditions under arthroscopic finding (ICRS grades) were compared with SPECT/CT grading. In all cases, there were increased uptakes on patellofemoral joints. Eighteen cases showed low uptake (Group 1), 22 cases showed medium uptake (Group 2) and 40 cases high uptake (Group 3). At the follow-up examination after mean 1.7 months, 16 cases of Group 1 (89%), 14 cases of Group 2 (64%) and 28 cases of Groups3 (70%) responded positively to the conservative treatments. For those 22 cases showing poor improvement, MRI and arthroscopy were done. Damage or thinning of patellofemoral cartilage, subchondral cyst, edema and fissuring were observed in every case that underwent MRI. Every arthroscopic case was found that there was patellofemoral cartilage damage. Each of ICRS grade I and grade II was found in 2 cases from Group 1. Two cases of grade II, 4 cases of grade III, and 2 cases of grade IV were found in Group 2. Two cases of grade II, 4 cases of grade III, and 6 cases of grade IV were found in Group 3. There was significant difference in the success rate of conservative treatment between SPECT/CT grade 1 and 2 or 3. And there was significant association between SPECT/CT grade and ICRS grade (P=0.034). SPECT/CT could be a useful modality in determining the treatment and prognosis for patellofemoral cartilage lesions compared with MRI and arthroscopic findings

Introduction. Obesity has been associated with higher complication rates and poorer outcomes following joint replacement surgery. Body mass index (BMI) is a simple index of body composition and forms part of preoperative assessment. It does not take into account the proportion of lean mass and body fat and can give a false impression of body composition in healthy manual workers. A more accurate measure of body composition is available using non-invasive bioimpedance methods. This study aims to identify whether BMI provides an accurate measure of body fat composition in patients awaiting lower limb arthroplasty surgery. Methods. Consecutive patients attending for pre-assessment clinic prior to total knee and hip replacement surgery were examined. All patients had their BMI calculated and underwent bioimpedance testing using a bedside Bodystat 1500 scanner (Bodystat, UK). Results. 83 patients (28 male) were included. Mean age was 68 years (range 16 to 92). All were awaiting lower limb arthroplasty surgery (39 primary total hip replacement, 4 revision total hip replacement, 38 primary total knee replacement, one unicompartmental knee replacement and one patellofemoral joint replacement). Mean BMI was 30.8 (range 20.8 to 48.9). Mean body fat percentage was 37.4% (range 17% to 53.9%). A weak correlation was seen between the calculated BMI and the measured body fat percentage (r=0.42, Pearson's correlation coefficient). Mean body fat percentage in obese patients (BMI > 30; mean BMI 34.9; n=42) was 42% while in the non-obese patients (BMI < 30; mean BMI 26.6; n=41) was 32.8%. This difference was significant (p<0.001). Conclusion. In patients undergoing lower limb arthroplasty the calculated BMI has a weak correlation with the measured body fat percentage. Bedside, non-invasive bioimpedance analysis provides a quick and accurate measure of body composition and can be used during preoperative assessment. Future correlation of outcome against body composition and BMI will validate the use of body composition in these patients. Care should be taken when relying on BMI alone to assess body fat composition

Objectives. For a long time lateral release (LR) was performed as a standard procedure both, for patellofemoral pain syndrome (PFPS) and patellofemoral instability (PFI). However, recent biomechanical studies have shown that LR is not useful for decreasing the lateral force onto the patella, but is increasing not only medial but also lateral PFI. Furthermore, pain on palpation over the lateral patellofemoral joint space can result in patients treated with extensive LR. We postulate that in case of persistent PFI or PFPS after failed LR the reconstruction of the lateral retinaculum as an addition of the reconstruction of the medial patellofemoral ligament (MPFL) is necessary in terms of decreasing medial PFI as well as lateral pain. Materials and Methods. In between 03/07 and 04/09 we have seen a total of 25 patients (20 f, 5 m) with persistent PFI and palpatory pain over the lateral retinaculum due to unsuccessful treatment of PFI with a LR. These patients have undergone revision surgery with an anatomical reconstruction of the released lateral retinaculum in combination with a reconstruction of the medial patellofemoral ligament (MPFL) in an aperture-technique using the gracilis tendon. The average age at time of operation was 26.2 ± 9.8 years. Preoperatively, as well as 6 weeks, 3 months, 6 months, and 12 months postoperatively, clinical examinations were performed and subjective as well as objective scores (Kujala-, Tegner-, IKDC-score) were evaluated. Regarding radiological parameters measurement of patellar tilt and shift was carried out on axial radiographs before and after the operation. Results. During the first twelve months after the operation only one redislocation could be recorded. Pain on palpation over the reconstructed lateral retinaculum was remaining in four patients (16%). Although several patients complained about persistent patellofemoral pain on exertion or after enduring flexion of the knee, all of them reported about an improvement of their pain situation. This fact is reflected in a highly significant improved but still moderate IKDC- (from 46.5 ± 14.9 to 68.9 ± 22.7, p<0.001) and Kujala-score (from 47.7 ± 15.3 to 74.8 ± 24.8, p<0.001) at the one year follow up. As far as sports activity is concerned, a statistically significant improvement of the Tegner-score up to 4.7 ± 2.4 (preoperative 2.3 ± 1.5, p<0.001) could be achieved. The radiological analysis showed a highly significant decrease of both, patellar tilt (from 15.4 ± 6.5 to 10.3 ± 6.2, p<0.001) and patellar shift (from 4.3 ± 3.3 to 2.5 ± 1.3, p=0.002). Conclusions. After one or more unsuccessful previous efforts of stabilizing the patella by LR, the technique performed in this essay leads to a considerable improvement of subjective scores and objective clinical and radiological parameters as well as sports activity

Introduction. We compared standard NexGen Cruciate substituting-flex prosthesis with gender-specific NexGen Cruciate substituting flex prosthesis in patients undergoing bilateral total knee arthroplasty with regard to Coverage of the bone by femoral component, Clinical outcome, Radiographic outcome, Survival and complication rates, with special emphasis on patellofemoral complications. Material & Methods. 30 female patients with osteo-arthritis of the knees with similar deformity and preoperative range of motion were randomized to have one knee replaced with a gender non-specific Nexgen Cruciate substituting (Zimmer) prosthesis and the other with Gender Cruciate substituting (Zimmer) prosthesis. Follow-up clinical evaluation was done at 6, and 12 months postoperatively and then at yearly interval using “Knee Society” Recommendations. Clinical assessment of the patellofemoral joint of the replaced knees was done with the help of “Hospital for Special Surgery” patellar scoring system. The overall patient satisfaction after surgery was evaluated with use of the British Orthopaedic Association patient satisfaction score. Results. The mean age was 63.8 years (range 49–76 years). 14 patients had standard NexGen Cruciate substituting-flex gender knee prosthesis on right side and 16 patients had on left side. On the other sides, standard NexGen Cruciate substituting-flex prosthesis implant was used. Preop Clinical findings were similar in both groups. The average Preop range of motion was identical in both the groups. The average follow up was 2.5 years (2–3.8 years). The mean post-operative Knee Society knee scores were 88,90,94, (70 to 100) and 87,92, 93 (70 to 100) points and the function scores were 83,85,88 (60 to 100) and 84.86.88 (60 to 100) points for the standard implants and the gender-specific designs, respectively at 6 months, 1 year and 2 year follow up. Mean improvement in patella score was 65, 71.1 and 73.3 points in Gender group at the end of 6 month, 1 yr and 2 yr respectively as compared to 65.6, 71.1 and 72.2 in Nexgen group. No patient had malpositioning of components or radiolucencies at the end of 2 year follow up. Mean improvement in BOA functional score was 20.6, 22.6 and 24.1 points in Gender group at the end of 6 months, 1 year and 2 year respectively as compared to 20.7, 21.8 and 23.2 in Nexgen group. In those with a standard prosthesis, the femoral component was closely matched in 30 knees, overhung in 17 and undercovered the bone in 13. In those with a gender-specific prosthesis, it was closely matched in 45 knees and undercovered the bone in 15. Conclusion. Although gender specific knee matched the femoral anatomy of Indian female knees better than the standard nexgen Knee, we found no significant differences between the two groups with regard to the clinical and radiological results, patient satisfaction or complication rate